Instrumentation and computer capabilities that measure, record, display and duplicate preconscious jaw movements have been developed. This Replicator System provides a basis for objective study and evaluation of occlusion. A partial listing of parameters investigated includes paths of movement of the central incisor, condyles and molars; instantaneous centers of rotation; and velocity characteristics of jaw movements. A data base for adult subjects with good occlusion and specific malocclusion has been established and a data base for young subjects in their growth and development period is underway. These data enhance the basic understanding of the neuromuscular control and guidance of the jaw. The data base for children with normal occlusion are being compared to the effects of treatment for 1) deep impinging anterior guidance using the Begg technique, 2) anterior open bite reduction through surgical intrusion of the posterior segments of the dental arch, 3) deficient mandible through anterior positioning with the Frankel functional appliance, and 4) condylar agenesis as seen in Branchial Arch Syndrome through maxillary repositioning and mandibular surgery. Patients with complete dentures are being studied to determine if one occlusal pattern would be more functional than another in denture patients. Patients in dysfunction, patients undergoing treatment and normal patients modified with the insertion of restorations with known occlusal interferences are being studied in relation to diagnosis of dysfunction and treatment evaluation. The recorded data will provide basic criteria for evaluation: 1) occlusal disharmonies, 2) TMJ disorders and 3) muscle dysfunction. These studies will lead to better dental treatment services as they relate to occlusion.